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[RFC] PR c++/44188

Message ID 871vcg2f6w.fsf@firetop.home
State New
Headers show

Commit Message

Richard Sandiford June 9, 2010, 7:12 p.m. UTC 
Dodji Seketeli <dodji@redhat.com> writes:
> commit d2c243d43b4809c72f4c9ed06caf4f382cf7fddf
> Author: dodji <dodji@138bc75d-0d04-0410-961f-82ee72b054a4>
> Date:   Thu May 27 19:29:53 2010 +0000
>
>     Fix PR c++/44188
>     
>     gcc/ChangeLog:
>     	PR c++/44188
>     	* c-common.c (is_typedef_decl): Move this definition ...
>     	* tree.c (is_typedef_decl): ... here.
>     	(typdef_variant_p): Move definition here from gcc/cp/tree.c.
>     	* c-common.h (is_typedef_decl): Move this declaration ...
>     	* tree.h (is_typedef_decl): ... here.
>     	(typedef_variant_p): Move declaration here from gcc/cp/cp-tree.h
>     	* dwarf2out.c (is_naming_typedef_decl): New function.
>     	(gen_tagged_type_die): Split out of ...
>     	(gen_type_die_with_usage): ... this function. When an anonymous
>     	tagged type is named by a typedef, make sure a DW_TAG_typedef DIE
>     	is emitted for the typedef.
>     	(gen_typedef_die): Emit DW_TAG_typedef also for typedefs naming
>     	anonymous tagged types.
>     
>     gcc/cp/ChangeLog:
>     	PR c++/44188
>     	* cp-tree.h (typedef_variant_p): Move this declaration to
>     	gcc/tree.h.
>     	* tree.c (typedef_variant_p): Move this definition to gcc/tree.c.
>     	* decl.c (grokdeclarator): Do not rename debug info of an
>     	anonymous tagged type named by a typedef.
>     
>     gcc/testsuite/ChangeLog:
>     	PR c++/44188
>     	* g++.dg/debug/dwarf2/typedef3.C: New test.

This breaks builds of libstdc++-v3 on mipsisa64-elf, where
__builtin_va_list is a record type.  We end up trying to output a
location for the definition of __builtin_va_list, which has location
UNKNOWN_LOCATION.  We then segfault in lookup_filename because the
filename associated with UNKNOWN_LOCATION is null.

Testcase is:

    typedef __builtin_va_list foo;

compiled with "./cc1plus -g".

A simple "fix" is attached, but many other built-in decls use
UNKNOWN_LOCATION, so I suspect something more fundamental is wrong.
Could you have a look?

Thanks,
Richard
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Patch

Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c	(revision 160501)
+++ gcc/c-family/c-common.c	(working copy)
@@ -4918,7 +4918,7 @@ 
   unsigned_ptrdiff_type_node = c_common_unsigned_type (ptrdiff_type_node);
 
   lang_hooks.decls.pushdecl
-    (build_decl (UNKNOWN_LOCATION,
+    (build_decl (BUILTINS_LOCATION,
 		 TYPE_DECL, get_identifier ("__builtin_va_list"),
 		 va_list_type_node));
   if (targetm.enum_va_list)